Adjusting SOC strength in VASP version >=6.4

[sophie_weber1]

Hello,

I would like to perform a set of calculations where I adjust the strength of spin-orbit coupling within the VASP code. I have seen some instructions online referring to modifying the relativistic.f90 source code file, but this was for versions 5x of VASP.

If you could clarify whether that's still the same for VASP versions 6.4 and above, and if so exactly which line to modify and how, I'd appreciate it.

Thank you very much in advance.

[max_liebetreu]

Hello,

Thank you for reaching out to us!
I will confer with my spin-coupling colleagues and get back to you - but in the meantime, so that I can convey to them the full picture and offer the best possible solution, could you perhaps:

• provide a link to the instructions you found (if you still happen to know where)?
• tell us more about the context in which you want to modify that strength?

Best regards,

[max_liebetreu]

Hello,

After discussing the matter with my colleagues, I can say that the approach is still the same for VASP 6.4+ as it was for VASP 5x. There is a line to adjust in relativistic.f90 that governs the strength of the coupling.

I hope that helps?

Best regards,

[sophie_weber1]

Hello,

Yes, this is what I was looking for, thank you so much!
This was the link that I saw before https://mattermodeling.stackexchange.co ... th-in-vasp
Just to confirm it will be the same line/variable to change, i.e. the prefactor in front of d0 in the term 0.5d0*SUM*LS(M,MP,I+2*J+1,LL)?

Thanks for your help again, I appreciate it!

Best
Sophie

[max_liebetreu]

Hello Sophie,

You are very welcome!
I just checked for VASP 6.5.1, where the line is now 132, but otherwise looks the same as far as I can tell. A factor of 0.5d0 reduces the strength by half, a factor of 0.0d0 will turn it off entirely.

Best,